User`s guide

LTI Properties
2-41
You can use regular cell array syntax for accessing or modifying I/O group
components. For example, to delete the first output group,
temperature,type
h.OutputGroup(1,:) = []
ans =
[1x2 double] 'measurements'
Similarly, you can add or delete channels from an existing input or output
group. Recalling that input group channels are stored in the first column of the
corresponding cell array, to add channel three to the input group
controls,
type
h.inputgroup{1,1} = [h.inputgroup{1,1} 3]
or, equivalently,
h.inputgroup{1,1} = [1 2 3]